The present invention relates to the field of processing lumber and more particularly to the art of planing a surface of workpiece to a desired thickness, and sanding the planed surface of the workpiece to finish its surface. With even more particularity, the present invention relates to a combination planer and sander machine that may be operated in either a planing and sanding configuration or a sanding-only configuration.
Planers and sanders are well known in the art and their function in shaping wood to a desired thickness is well known. Combination planers and sanders are used to both size and finish workpieces. These machines have a planing station comprising at least one driven planer head that is used to size workpieces to a predetermined thickness, and also a sanding station that typically includes at least one driven sander head that is used to finish the planed surface of the workpiece. Conveyors are utilized to feed workpieces through a planer and sander along a feed path and in a feed direction.
Combination planers and sanders have several safety features, including antikickback fingers and chip-break shoes that ride over the upper surface of the workpiece prior to planing. Antikickback fingers prevent a workpiece from moving through a sander and planer in a direction opposite the feed direction, which can be caused by the blades of a rotating planer head digging into the surface of a workpiece and driving it backwards, instead of planing the surface of a workpiece as it proceeds along a feed path in the feed direction. The distal end of antikickback fingers ride along the surface of the workpiece as the workpiece travels in a feed direction. In the event a workpiece is driven backwards, the forward edge of the antikickback fingers dig into the upper surface of the workpiece and the antikickback fingers rotate about a holding bar in direction tangentially opposite the feed direction until such rotation is halted by a stop member. In this manner, the antikickback fingers halt the backward motion of a workpiece and prevent it from backing out of the machine at its inlet.
Chip-break shoes, another safety device in combination planers and sanders, prevent significant damage to the quality of a workpiece resulting from chipping along a woodgrain by operation of the planer head. The distal ends of chip-break shoes ride along the surface of the workpiece, and if the planer head should cause a chip to form along a woodgrain, such formation would result in a lifting of the upper surface of the workpiece. Without a chip-break shoe, the formation of the chip would be allowed to continue unimpeded potentially deep into the workpiece, thereby risking significant damage to the workpiece. The chip-break shoes prevent the upward movement of the surface of the workpiece, causing the chip to break off at the forward end of the chip-break shoes. Because the chip-break shoes are positioned proximate the planer head, chips are broken off by the chip-break shoes almost immediately upon formation and significant damage to the workpiece is thereby prevented.
Normally a planer and sander machine is utilized for both sizing and finishing workpieces, that is, it is used in its normal configuration for both planing and sanding. In some instances it is desirable to only sand/finish workpieces and not to also plane/size workpieces. For instance, operation of a sanding-only configuration is often desirable for veneered parts and cabinet doors with stiles and rails. To place a machine in a sanding-only configuration, the planer head must be adjusted vertically so that it is above the sanding passline, in which case the planer head will not contact the workpiece. However, utilizing the planer and sander in this configuration can cause damage to the workpiece on account of the operation of the antikickback fingers and chip-break shoes, which ride long the upper surface of the workpiece. Practice has demonstrated that antikickback fingers and chip-break shoes will scratch the stiles of a door and any veneered surface, and the scratches will often be deeper than the amount of stock being subsequently removed by the sanding station. Thus, for those workpieces for which processing in a sanding-only configuration is desired, operating a planer and sander with the antikickback fingers and chip-break shoes engaging the surface of the workpiece significantly degrades the quality of the finished product.
To operate a planer and sander in a sanding-only configuration, it is necessary to either remove the antikickback fingers and chip-break shoes from the machines altogether or to otherwise move them so that the antikickback fingers and chip-break shoes do not engage a workpiece as it is being processed. Conventional methods of converting a planer and sander from a planing and sanding configuration to a sanding-only configuration are time consuming and difficult, thereby placing significant limitations on the capacity of planer and sander machines to conduct both planing and sanding operations and sanding-only operations.
What is needed is an improved apparatus for sizing and finishing a workpiece that is easy to use, inexpensive to maintain, and allows for readily changing the operation of the apparatus from a planing and sanding configuration to sanding-only configuration. A need exists for an improved planer and sander machine that will greatly speed up the change-over time required to change the configuration of the machine.
It is an object of the present invention to provide an improved combination planer and sander machine.
A further object of the present invention is to provide a combination planer and sander machine that can be easily and quickly converted from a planing and sanding configuration to a sanding-only configuration.
Another object of the present invention is to provide an apparatus for sizing and finishing workpieces that has a sizing station and a planing station having a means for disengaging the planing station to convert the apparatus from a planing and sanding configuration to a sanding-only configuration.
Another object of the present invention is to provide an apparatus for sizing and finishing workpieces having a planing station comprising an antikickback assembly and a chip-break assembly, and means for automatically raising the lowermost portion of the antikickback assembly and chip-break assembly so that the assemblies do not engage a workpiece.
These and other objects of the present invention are accomplished through the use of a combination planer and sander machine for sizing and sanding solid workpieces. The machine has a housing defining a horizontally throughgoing passage extending along a feed path, and a driven feed conveyor onto which a workpiece is fed through the machine along a feed path. The feed conveyor carries the workpiece through the machine along a horizontal feed path, the upper surface of the workpiece passing through the machine along a pass line.
The invention further comprises a planing station that sizes a workpiece along its upper surface and a sanding station that finishes the surface of the workpiece after it has been planed. The planing station of the present invention comprises a planer head, an antikickback assembly, chip-break assembly, and means for disengaging the planing station to convert the apparatus from a planing and sanding configuration to a sanding-only configuration.
The antikickback assembly comprises a plurality of antikickback fingers extending downward from a positioning rod to form a row of antikickback fingers. Each antikickback finger has a lower end terminating in a forward edge. Each antikickback finger is rotatably mounted on the positioning rod and positioned to rest against a cam shaft assembly that acts as a stop limiting rearward motion of the antikickback fingers. Means for disengaging the planing station comprises positioning means for automatically raising the lowermost portion of the antikickback assembly above the passline B. The present invention provides for rotating the cam shaft assembly to raise the lowermost portion of the antikickback assembly, which is accomplished by activating an air operated cylinder or similar actuator having a piston rod pivotally connected at its distal end to a link member connected to the cam shaft assembly. The movement of the piston rod causes the cam shaft assembly to rotate about its longitudinal axis, with the concomitant pivotal movement of the antikickback fingers about the positioning rod so that the lowermost end of the antikickback fingers are positioned above the pass line B.
The chip-break assembly comprises a plurality of chip-break shoes extending from a horizontal holding bar to a distal end terminating in a sharp edge at the forward-most portion of the chip-break shoes. The chip-break shoes are positioned in close side-by side-relationship to form a row of chip-break shoes, each shoe having an essentially continuous upper lower, and bottom surfaces transverse of the direction of the feed path. The holding bar is attached at its ends to the distal end of bracket members that are pivotally connected at the proximal ends thereof to the housing. Means for disengaging the chip-break assembly comprise positioning means for lifting the lowermost portion of the chip-break shoes above the pass line B, which is accomplished by lifting the distal end of the bracket members that support the holding bar proximate the holding bar and chip-break shoes, so that the bracket members rotate about the pivot point being its point of connection to the housing. Lifting the distal end of the bracket members is accomplished by activating an air operated cylinder, or similar actuator, connected to the housing, having a piston rod fixedly connected at its distal end to the bracket members. Retracting the piston rod lifts the lowermost portion of the chip-break shoes above the pass line B.
The present invention further comprises an electrical control means comprising at least one switch for initiating the concomitant operation of the means for automatically raising the lowermost portion of the antikickback assembly above the passline B, the means for automatically lifting the lowermost portion of the chip-break assembly above the passline B, and means for automatically disabling the motive force to the driven planer head. The electrical control means allows the combination planer and sander machine to be readily switched from a planing and sanding configuration to a sanding-only configuration, whereby a workpiece is finished by the sanding station without being sized by the planing station or being engaged by the antikickback or chip-break assemblies.
These and other objects and advantages of the invention will become apparent from the following detailed description of the preferred embodiment of the invention.